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Benthic and Deep-water Environments

SS08: Biogeochemistry of Metal-binding Organic Ligands in the Ocean: Sources, Composition and Impacts on Trace Metal Cycling — See Schedule

Conveners:Maeve C. Lohan, University of Plymouth, maeve.lohan@plymouth.ac.uk; Sylvia G. Sander, University of Otago, sylvias@chemistry.otago.ac.nz; Kristen N. Buck, Bermuda Institute of Ocean Sciences, kristen.buck@bios.edu

The bioactive trace metals iron, copper, cobalt, nickel, zinc and cadmium are essential micronutrients for marine phytoplankton and exert a major influence on the global carbon cycle. Complexation of these metals by organic ligands may enhance or reduce bioavailability depending upon the metal-ligand complex formed. Yet we know little about the composition, sources and cycling of metal-binding ligands, which is hindering further advances in the field of trace metal biogeochemistry. An active SCOR Working Group (WG 139) ‘Organic Ligands- A Key Control on Trace Metal Cycling in the Ocean’ fosters the multidisciplinary collaboration of trace metal biogeochemists, organic geochemists and biogeochemical modelers in order to advance this field. This session is a community wide forum to highlight recent accomplishments in metal-binding ligand characterization and approaches for assessing ligand composition, sources and impacts on trace metal cycling in the aquatic environment, and to discuss future efforts in this field. We welcome abstracts related to metal- binding ligands from throughout the multidisciplinary field of oceanography.

SS14: Natural and Anthropogenic Driven Responses of Microbial Communities in the Ocean: Effects on the Biological and Microbial Carbon Pumps — See Schedule

Conveners:Richard B. Rivkin, Memorial University of Newfoundland, Canada, rrivkin@mun.ca; Louis Legendre, Laboratoire d'Oceanographie de Villefranche, France, legendre@obs-vlfr.fr; M. Robin Anderson, Fisheries and Oceans Canada, Canada, m.robin.anderson@dfo-mpo.gc.ca

Over 25 years ago, it was proposed that the biological carbon pump (BCP) transfers particulate organic carbon (POC) from surface waters into the deep ocean. Recently, it was suggested that in a parallel process, the microbial carbon pump (MCP) lengthens the residence time of carbon in the ocean through the production of refractory dissolved organic carbon (DOC) by heterotrophic prokaryotes. Both pumps lead to the sequestration of atmospheric CO2 in the ocean. Ongoing studies on responses of marine microbial communities to drivers that are both natural (e.g. atmospheric and ocean circulation, mixing) and anthropogenic (e.g. acidification, eutrophication, increased temperature) contribute to better understanding of the functioning of the two pumps. Microbes influence both the BCP (e.g. effects on community respiration or solubilisation of POC) and the MCP (e.g. effects on production of refractory DOC). This session invites marine microbiologists, biogeochemists, environmental scientists and modellers to report on empirical, synthetic and/or model studies that contribute to our understanding of the responses of the microbial community to the above drivers, and the consequences for carbon sequestration through the microbial and biological carbon pumps.

SS16: Opportunities in the Study of Ocean Particle Flux — See Schedule

Conveners:Adrian Burd, University of Georgia, adrianb@uga.edu; Oscar Schofield, Rutgers University, oscar@marine.rutgers.edu

The vertical flux of particulate material in the oceans plays both direct and indirect roles in biogeochemical cycles and ecosystems of the ocean. Sinking particles redistribute carbon and other elements vertically in the ocean, supplying food to deep-sea organisms and contributing the ocean uptake of carbon from the atmosphere. Although recent studies have shed light on the fate of particulate material in both surface and mid-waters of the ocean, we still have a poor understanding of the drivers affecting changes to particulate material as it sinks, and models are still unable to accurately reproduce observations of particle flux. This session aims to bring together those interested in understanding particle flux in the ocean with an aim of synthesizing our current understanding and initiating discussions for future directions in this field. We invite submissions from field researchers and modelers to present in this session.

SS18: Oxygen Minimum Zones and Climate Change: Impacts on Higher Trophic Levels — See Schedule

Conveners:Karen Wishner, University of Rhode Island, kwishner@gso.uri.edu; Lisa Levin, Scripps Institution of Oceanography, UCSD, llevin@ucsd.edu; Brad Seibel, University of Rhode Island, seibel@uri.edu

Oxygen minimum zones may be expanding in the world’s oceans in response to global climate change. These regions are also locations of high carbon dioxide, so animals may be affected by the multiple stressors of low oxygen and increasing acidification. For metazoans, physiological constraints, along with changes in ecological and environmental interactions, may result in changes in abundances, vertical distributions, migration patterns, and life history strategies. Potential community and ecosystem impacts include habitat compression affecting fisheries and benthos, alterations in biological pump processes and biogeochemical cycles, and changes in benthic-pelagic coupling. We seek presentations on these effects, focused on metazoans from zooplankton and meiofauna to top predators and megafauna. Contributions dealing with educating students and the public about potential human impacts and seeking solutions to public concerns are also welcome.

SS30: Biological and Biogeochemical Responses to Human Impacts at the Sediment-Water Interface — See Schedule

Conveners:John Lehrter, EPA Gulf Ecology Division, lehrter.john@epa.gov; Katja Fennel, Dalhousie University, katja.fennel@dal.ca; Wally Fulweiler, Boston University, rwf@bu.edu; Roxane Maranger, University of Montreal, r.maranger@umontreal.ca

Human impacts to aquatic ecosystems often manifest at the sediment-water interface. Local and regional scale issues such as eutrophication, sedimentation and resuspension of inorganic and organic particles, toxic pollution, and over-fishing can have dramatic effects on benthic biological communities (ranging from microbial organisms to mega fauna) and induce feedbacks to the water column by altering biogeochemical processes. Recently, there is increasing awareness of compounding effects by global scale phenomena such as rising sea surface temperatures and ocean acidification. However, despite advancements in the theory, observation, and modeling of communities and biogeochemical processes at the sediment-water interface that have occurred over the last several decades, many regulating mechanisms are still poorly characterized. Hence, our ability to accurately predict and mitigate the impacts of human activities is hindered. This session invites investigators to present and discuss recent observational or modeling studies that add to our understanding of processes at the sediment-water interface. Presentations that integrate or synthesize across multiple spatial and temporal scales or levels of functional organization, genes to ecosystems, are encouraged. Non-research presentations that provide environmental policy perspectives and challenges, which may inform knowledge gaps and research needs, are also encouraged.

SS34: Biogeochemistry of Resuspended Sediments in Aquatic and Coastal Marine Environments — See Schedule

Conveners:John R. Helms, University of North Carolina Wilmington, helmsj@uncw.edu; Stephen Skrabal, University of North Carolina Wilmington, skrabals@uncw.edu; G. Brooks Avery, University of North Carolina Wilmington, averyg@uncw.edu; Ralph Mead, University of North Carolina Wilmington, meadr@uncw.edu

Sediment-water interactions during resuspension events can significantly impact a number of biogeochemical processes such as trace metal mobilization, nutrient and organic matter cycling, and release of anthropogenic contaminants. We invite papers on any biogeochemical aspect of sediment resuspension in coastal marine and aquatic environments. In particular we encourage contributions on how these processes might be influenced by global climate change (e.g. rising sea level) and land use changes.

SS48: Geochemical Consequences of Advection in Aquatic Sediments — See Schedule

Conveners:Andreas Brand, Eawag, Surface Water Group, andreas.brand@eawag.ch; Joerg Lewandowski, IGB Berlin -Ecohydrology group, lewe@igb-berlin.de; Gunnar Nuetzmann, IGB Berlin -Ecohydrology group, nuetzmann@igb-berlin.de; Christof Meile, Department of Marine Sciences, University of Georgia; cmeile@uga.edu

Porewater advection is critical for the understanding of early diagenesis in many aquatic settings. Some of these processes such as wave-induced porewater advection and the pumping activity of animals such as Arenicola marina have been closely investigated in marine environments. In addition, recent studies suggest that porewater advection is also a key process in limnic sediments. For example, tube dwelling fauna can induce porewater advection in the sediment surrounding their burrows due to their pumping activity, and porewater advection can become the dominant transport mechanism in sediments close to the thermocline in lakes with intense seiche activity. Furthermore, groundwater discharge can be the dominant transport mechanism in the open water – sediment – groundwater discharge transition zone. Since sediments are typically highly reactive, the turnover rates of organic carbon, nutrients, oxygen and other electron acceptors are tightly coupled to the transport processes which govern the supply of chemical compounds. In this session we aim to discuss novel approaches ranging from experimental investigations in the laboratory and in situ at various scales to numerical studies which investigate the impact of advection on biogeochemistry.

SS58: Ocean Provinces, Food Web Structure and Particle Flux — See Schedule

Conveners:Uta Passow, Marine Science Institute, University of California Santa Barbara, passow@lifesci.ucsb.edu; Adrian Burd, Department of Marine Sciences, University of Georgia, adrianb@uga.edu; Deborah Steinberg, Virginia Institute of Marine Science, debbies@vims.edu

Spatial and temporal variations in export particle flux from the surface ocean depend in part on the variability of the surface food web structure which varies geographically. Remineralization of particles below the surface layer depends largely on the food web structure underlying the surface waters. This session aims to present research related to geographical variability in surface and deep water food web structure and how it controls variability in particle flux and remineralization. This session will be of interest to biogeochemists, surface and deep water ecologists, phytoplankton specialists, ecosystem or biochemical modelers and those interested in zooplankton and higher trophic levels in both the surface and deep ocean, who strive for a mechanistic understanding of processes driving particle flux.

SS75: Role and Significance of Chemosynthesis in the Ocean — See Schedule

Conveners:Karen G. Lloyd, University of Tennessee, klloyd@utk.edu; Stefan Sievert, Woods Hole Oceanographic Institution, ssievert@whoi.edu

Chemosynthesis is increasingly recognized to be more widespread and of larger significance in the ocean than previously thought. However, while a future ocean is expected to lead to an expansion of oxygen minimum zones supporting chemosynthetic processes, we currently lack a basic understanding of the main players, the pathways involved, and the regulation of energy and carbon transfer. This is even true for such charismatic environments as hydrothermal vents and cold seeps, where the general role and importance of chemosynthesis is well documented. Recent research further indicates that chemosynthesis plays a critical, yet currently poorly constrained role in other parts of the ocean system, most notably oxygen minimum zones and the deep-ocean subsurface. Recent advances in ‘omic’ technologies, functional assays of enrichments, and single-cell analysis make it now possible to obtain insights into the function of these microbial communities at an unprecedented level. Linking these ‘omic’ approaches to geochemical investigations and incorporating these data into innovative models presents great opportunities to advance our understanding of chemosynthetic communities and processes. Submissions from different lines of investigations using these approaches either in isolation or in combination are encouraged.